Gas fired water heaters or tanks are quite well known. In such units, cold water, or water at ambient temperature, is introduced into the tank through an intake pipe and heated by a gas burner. The heated water is then passed from the tank through an output pipe upon demand. In the prior art, flue gasses from the tank burner have been emitted at elevated temperatures, requiring high temperature exhaust pipes such as those provided by steel or fire brick chimneys. The elevated temperature of the flue gases provided for the exhaust thereof. The natural rise of the hot flue gases, coupled with the draw or draft provided by the chimney assured the exhausting of the burner gases from the hot water tank and from the building in which it was maintained.
Presently, power venting high efficiency hot water tanks have become quite common. In such units, the temperature of the flue gases is low. Indeed, the flue gas temperature is so low that the exhaust gases can be passed through plastic or PVC pipe and through the wall of the associated building, rather than up a chimney or other elevated exhaust pipe. Not only was the efficiency of hot water heaters increased with such prior art units, but the exhausting of the flue gases was greatly simplified and the incident costs reduced. However, the reduced temperatures of the exhaust gases, coupled with the absence of an elevated chimney or exhaust pipe has generally resulted in the necessity of the inclusion of an exhaust fan to assure that the exhaust gases or fumes are drawn from the burner and expelled through the plastic pipe to the exterior of the building.
Previously known exhaust fans for hot water heaters have been complex in structure, inefficient in use, and expensive to manufacture and purchase. Typically, prior art exhaust fans for hot water tanks and similar burners have not provided for a fan which is axially aligned with the exhaust flue. Typically, the fan has been horizontally mounted above the hot water tank for communication with the flue through a shroud or vent positioned thereover. Additionally, the prior art has typically taught the use of a separate motor cooling fan for such assemblies, rather than allowing the exhaust fan to serve as the motor cooling fan as well. Additionally, prior art exhaust fans of the type under consideration have not been configured or contained in a housing readily adapted to be received between the input and output water pipes and over the exhaust flue or vent.
There is a need in the art for an exhaust fan for water heaters which eliminates the problems of the prior art noted above.